<?php
/**
 * I use this function to generate microsoft-compatible GUID's.
 */
function create_guid($namespace = '') {     
	static $guid = '';
	$uid = uniqid("", true);
	$data = $namespace;
	$data .= $_SERVER['REQUEST_TIME'];
	$data .= $_SERVER['HTTP_USER_AGENT'];
	$data .= $_SERVER['LOCAL_ADDR'];
	$data .= $_SERVER['LOCAL_PORT'];
	$data .= $_SERVER['REMOTE_ADDR'];
	$data .= $_SERVER['REMOTE_PORT'];
	$hash = strtoupper(hash('ripemd128', $uid . $guid . md5($data)));
	$guid = '{' .   
		substr($hash,  0,  8) . 
		'-' .
		substr($hash,  8,  4) .
		'-' .
		substr($hash, 12,  4) .
		'-' .
		substr($hash, 16,  4) .
		'-' .
		substr($hash, 20, 12) .
		'}';
	return $guid;
}
  
echo create_guid();